1. Field of the Invention
The present invention is directed to an apparatus for disintegrating solid waste to form a pulp for disposal.
2. Description of the Related Art
Waste reduction systems such as solid waste pulpers have been in use for many years. One such system is disclosed in Altonji et al., U.S. Pat. No. 5,577,674, assigned to the assignee of this application, the disclosure of which is incorporated herein by reference. In typical systems such as that in U.S. Pat. No. 5,577,674, waste from a kitchen or another waste source is placed into a pulping tank partially filled with water. A cutting or grinding mechanism is installed near the bottom of the tank and usually includes a rotating impeller with attached rotating blades that periodically come into play with stationary blades attached to a sieve ring. A grinding motor rotates the impeller, causing the blades to grind the solid waste into a pulp of small particles and circulate the water and solids within the tank. Waste particles that are sufficiently small to pass through the sieve ring are discharged from the tank and away from the pulping unit to an extractor to remove water from the slurry. In close-coupled systems such as in U.S. Pat. No. 5,577,674, the force of the rotating blade and a set of pumping ears are used to move the slurry a short distance to the extractor. In many prior art pulping systems, a slurry pump having a separate drive from the grinding motor is used to pump the slurry to a remote extractor.
Traditionally, the pulping capacity, or how much waste a pulper can process in a given period of time, has been thought to depend on the size of the pulper""s components, specifically, the pulping tank volume and the rotating blade diameter. If a large pulping capacity was needed, a large tank and a large rotating blade were provided.
The slurry is usually sent to a liquid extractor for drawing water out of the slurry and returning the extracted water to the tank. In some pulping systems, a portion of the extracted water, or xe2x80x9creturn water,xe2x80x9d is directed to a feed tray where the solid waste is placed. The return water is used to flush the solids down the tray into the pulping tank.
Different downstream environments for pulpers and extractors are common in waste reduction systems. One is a close-coupled system, where the pulper and extractor are in close proximity to each other so that the slurry does not need to be pumped very far, usually a few feet or less, to reach the extractor. Another is a remote system where the pulper and extractor are not in close proximity and the slurry pump must move the slurry a much greater distance, as much as 100 feet or more.
It has been necessary for the pulping system to be designed depending on whether a close-coupled or a remote system will be used by a particular customer, and what type of pulping it will be used for. For example, two restaurants may order the same pulper and extractor, but place them in different configurations so that one restaurant has a remote system where the pulper and extractor might be 100 feet apart and the other has a close-coupled system that requires a pump with a much lower pumping capacity than the first restaurant. Different pumping capacities are needed in different pulping situations as well. One customer may need a system to pulp large amounts of heavy material so that the slurry pump or pumping ears are required to move more dense slurry than another customer who may not have as intense pulping needs.
Because of varying customer needs like the above examples, a supplier typically has been required to maintain an inventory of pumps or pumping ears of various capacities so that the system will provide the desired flow rate for the anticipated slurry. In the above examples, the supplier would have to have an inventory with at least a high capacity slurry pump for the pulper of the first restaurant, and a low capacity slurry pump or set of pumping ears for the pulper of the second restaurant.
A problem that can occur with pulpers is the buildup of fibrous debris at the sieve ring or rotating blades. This buildup, also known as xe2x80x9cbridgingxe2x80x9d or xe2x80x9clogjamming,xe2x80x9d can cause blockage of the sieve ring that can back up the pulping system which can have a negative impact on the pulping efficiency of the system.
Another problem associated with many pulpers is the translation of vibrations between the pulping tank and its surroundings, particularly to the frame of the pulper. In an exemplary case of this problem, pulpers may include a table as part of the frame so that a restaurant""s employees may place dishes on the table to conserve space. As the pulper is used, vibration is translated to the frame from the tank, and then to the table, causing the dishes to vibrate. This can be very noisy as the dishes vibrate and clatter. This is very undesirable for the restaurant, as it is annoying and distracting to the customers and the employees.
Yet another problem that can occur with pulpers has to do with the feed tray. Many pulping systems operate at a flow rate which results in a turbulent, splashing flow of the return water within the feed tray. At high enough flow rates, the return water can splash wildly out of the tray. This would also be undesirable because the mess must be cleaned up repeatedly.
What is needed is a pulper that allows for easy modification between close-coupled systems and remote systems. Also what is needed is a pulper that keeps fibrous debris clear of the sieve ring and rotating blade to prevent blockage and backup of the pulping system. Further, what is needed is a pulper that minimizes the translation of vibrations between the pulping tank and its surroundings. Additionally, what is needed is a feed tray that minimizes splashing in the feed tray.
In accordance with the present invention, an impeller assembly for a waste pulping apparatus is provided, the impeller assembly including a rotating blade for pulping the waste to form a slurry, the rotating blade having an axis of rotation, a base and a plurality of ears that axially extend away from the base. The impeller assembly also includes a sieve ring having axially opposed first and second ends, an inner cylindrical surface and an outer cylindrical surface. The sieve ring encircling the base of the rotating blade at the first end. At least a portion of the ears are radially spaced inside the inner cylindrical surface so that the ears rotate within the sieve ring. A plurality of pumping vanes are also provided for pumping the slurry, where each pumping vane has a pumping surface that rotates radially around the outside the outer cylindrical surface of the sieve ring. Preferably, the pumping vanes can be easily changed to allow for various head condition while providing a predetermined pumping capacity.
Also in accordance with the present invention, a waste pulping apparatus is provided having a tank for containing liquid and waste to be pulped and a slurry chamber adjacent to the tank. The impeller assembly is mounted to the tank at the slurry chamber and further includes at least one stationary blade adjacent to the inner cylindrical surface at the second end of the sieve ring and axially extending from the second end so that the stationary blade is in close proximity to the ears of the rotating blade.
Also in accordance with the present invention, a method of assembling an impeller assembly for a waste pulping apparatus is provided, the method including the steps of providing a rotating blade and a sieve ring of the impeller assembly described above, selecting a plurality of matching pumping vanes, each having a pumping surface for providing a predetermined pumping capacity against a predetermined head and connecting each one of the plurality of selected pumping vanes to the impeller so that each pumping surface rotates radially outside of the outer cylindrical surface of the sieve ring.
Also in accordance with the present invention, a waste pulping apparatus is provided, the apparatus including a tank for containing liquid and solids, the tank having an upper portion with a perimeter, a frame for supporting the tank, a means for pulping the liquid and solids within the tank, a shell having a lower portion with a perimeter, where the lower portion of the shell and the upper portion of the tank are nested defining a juncture between the tank and the shell at the perimeters. A seal is placed at the juncture for preventing the liquid and solids from leaving the tank and for minimizing the translation of vibrations between the tank and the shell, and a plurality of mounting brackets are placed between the tank and the frame for minimizing the translation of vibrations between the tank and the frame.
Also in accordance with the present invention, a feed system for a waste pulping apparatus is provided, the feed system including a tray for feeding the liquid and the solids into the tank, the tray having an inlet for receiving liquid and a width, and a means for distributing the liquid at the inlet of the tray for evenly distributing the liquid across the width of the tray. In one embodiment, the means for distributing the liquid is a dispersion plate at the inlet of the tray.
Also in accordance with the present invention, a waste pulping apparatus is provided including a tank having means for pulping waste solids into a slurry, a means for pumping the slurry where the pumping means are operatively connected to the tank, an extractor mounted proximate to the tank for receiving slurry and extracting liquid from the slurry, a return pump connected to the extractor for returning the liquid to the tank, wherein the extractor mount is a quick-release mount to facilitate easy access to the return pump.
These and other objects, features and advantages are evident from the following description of an embodiment of the present invention, with reference to the accompanying drawings.